Whatever your obsession is, there is a feared consequence that fuels the leap into compulsions. This is useful information for constructing exposures. The irony is that OCD claims to protect you from whatever consequences you fear, but can instead bring on those consequences. I notice this with reading obsessions.
I sometimes get the thought that I might not truly understand what I just read, so I go back and read it again, and again, and get stuck on one page. The rereading is the compulsion, in an attempt to prevent misunderstanding, and yet this makes it even harder for me to understand what I am reading, because I am disrupting the flow of the writing. An exposure would be to keep reading, even if I'm not sure I understand.
This also happens with conversations, and a desire to include every possible detail the other person needs to understand fully. This made my sessions with my exposure therapist a challenge at first, because my efforts to include everything made it difficult to focus on anything. I feared he wouldn't be able to help me if I wasn't absolutely thorough, but humans can't convey every possible fact in an hour, and it actually is overwhelming to be listening to this, and makes it harder for the other person to understand.
Jonathan Grayson has a section about these obsessions and tactics for doing exposures in his book Freedom From OCD.